| Objectives: Flt3 (Fms-like tyrosine kinase-3) is a number of the class Ⅲreceptor tyrosine kinase family and plays an important role in regulating the proliferation, differentiation and survival of hematopoietic cells by the activation of the extracelluar tyrosine residues and subsequent signal transduction. Flt3 may also enhance proliferation and survival of leukemia blasts. Flt3 ligand, FL, can exert more effective and potent abilities in hematopoietic system by binding itself to Flt3. Some of acute leukemia patients displayed both receptor and ligand mRNA suggesting a possible autocrine or intracrine stimulation. Moreover, FL can stimulate the proliferation and differentiation of hematopoietic cells and improve the ability of hematopoiesis of the economy. The study was to investigate the relationship between the expression of Flt3/FL and the development of acute leukemia, then to investigate whether there was some relationship between the coexpression of Flt3/FL and the pathogenesis of acute leukemia. Moreover, we examined the variety of concentration of FL in the chemotherapy process of the acute leukemia patients, in order that it can become a new hematopoietic growth factor in the appliance of the clinic someday. Methods: The expression of Flt3 and FL mRNA were measured in 106 acute leukemia patients (including 64 de novo acute leukemia patients, 12 relapsed patients, 30 complete remission patients), 19 samples of normal controls (NC) and K562, KG-1αand HL60 cell lines by semi-quantity reverse transcription-polymerase chain reaction (RT-PCR). The concentration of FL was measured in 12 acute leukemia patients (including 7 de novo acute leukemia patients, 5 complete remission patients) before chemotherapy, 5 to 7 days and 20 to 30 days after the chemotherapy by ELISA. The investigation also adopted 5 samples as normal control (NC). Results: 1 The expression of Flt3 and FL mRNA in AL patients 1.1 The expression of Flt3 mRNA in de novo AL patients (mean 0.753±0.576,positive rate 70.31%) and in relapse (RP) AL patients (mean 0.802±0.693,positive rate 83.33%) were significantly higher than NC (mean 0.182±0.050, positive rate 36.84%) (P < 0.05). But there was no difference between de novo group and RP group and there was also no difference between AML (mean 0.864±0.726, positive rate 68.89%) and ALL group (mean 0.438±0.127, positive rate 73.68%) (P>0.05). The expression of Flt3 mRNA in AML and ALL were higher than that in NC (P<0.05); but there was no difference between CR-patients (mean 0.366±0.293, positive rate 43.33%) and NC. The expression of Flt3 in AL group and RP group were higher than that in CR group (P<0.05).1.2 The untreated AL patients were divided into Flt3-positive group and Flt3-negative group. The CR rate was 64.44% in Flt3-positive group, significant lower than that in the Flt3-negative group (CR rate 89.47%) (P<0.05). 1.3 According to the tracking examination of 20 patients, the level of Flt3 of untreated AL patients (0.753±0.576) decreased significantly when they got CR (0.370±0.294). But when part of them relapsed, the level of Flt3 increased again obviously (0.810±0.703). 1.4 The mean expression of FL mRNA in de novo AL patients was 0.445±0.275, the positive rate was 51.56 %. In the RP-patients, the mean expression was 0.390±0.256, the positive rate was 50.00%. In the CR-patients, the mean expression was 0.369±0.288, the positive rate was 36.67%. In the NC group, they were 0.412±0.281 and 52.63% separately. The expression of FL mRNA in the four groups had no statistical difference (P>0.05). 1.5 The untreated AL patients were divided into FL-positive group and FL-negative group. The CR rate was 72.73% in FL-positive group, and there was no difference between the FL-positive group and the FL-negative group (CR rate 70.97%) (P>0.05). According to the tracking examination of 20 patients, the level of FL did not have obvious change during the different stage of chemotherapy. 1.6 There were 34.38 % de novo AL patients measured to express both Flt3 and FL mRNA.1.7 There was n... |
PDF Full Text Request